In a new study, researchers used EEG on newborns to see if they could quantify brain changes associated with consuming alcohol and tobacco during pregnancy.
They found that both alcohol and tobacco consumption were associated with EEG changes. For alcohol this manifested as an increase in low-frequency brain activity in the temporal lobe. With tobacco, researchers observed a decrease in high-frequency brain activity in the central brain.
The scientific community has long known that alcohol and tobacco consumption during pregnancy can have a long-term negative impact on a child’s health. What is still not known, however, is just how much it takes to cause this negative effect, and what the mechanism of that effect looks like.
This study aims to fill in these gaps. The research included 1,739 infants and their mothers from the Northern Plains region of the U.S. and Cape Town, South Africa. Before birth, pregnant women were recruited and asked about their alcohol and tobacco use. Based on their answers they were divided into groups, with consumption quantified as follows:
- No alcohol/tobacco
- Low but continuous use of alcohol/tobacco
- Moderate or high continuous use of alcohol/tobacco
Once the babies were born, researchers collected the infants’ EEG data during natural sleep cycles using “a hybrid system of a 28-lead high-impedance electrode net (Electrical Geodesics) and a miniature amplifier recording device (ATES),” according to the study’s authors.
We asked Dr. Sophia French, a child neurologist at Oregon Health and Science University in Portland, Oregon, to help us understand this study’s results. The following are excerpts from our questions and her answers, lightly edited for clarity:
Neurology Insights: What is the significance of low-frequency brain activity at the temporal lobe in an infant?
French: This study tells us that there is a dose-dependent association between prenatal exposure to alcohol and increased theta and alpha EEG power in the left temporal region at term. These frequency ranges are normal in term neonates and do not clearly suggest underlying white matter dysfunction.
The left temporal lobe is important for memory formation, emotion, and language. It is possible that increased theta and alpha frequencies in the left temporal lobe are reflective of left temporal disruption that leads to the memory difficulties and mood lability seen in people with fetal alcohol syndrome.
This study also shows that prenatal exposure to tobacco causes increased beta and gamma activity in the neonate. We know that exposure to nicotine (similar to barbiturates, benzodiazepines, and cocaine) can cause a transient increase in beta activity without any clear clinical significance.
Neurology Insights: What are the long-term developmental implications of seeing EEG changes like this in a newborn during sleep?
French: It is not possible to extrapolate definitive long-term developmental implications of subtle changes in EEG background frequencies at term. EEG gives information about how the brain is functioning in the moment. These subtle variations in EEG background following extended exposure to a noxious substance could be transient and have no prognostic value or could be an early indicator of clinically meaningful brain injury.
Neurology Insights: Do you have any comments or interpretation of this study you feel are relevant to EEG technologists?
French: Prenatal alcohol exposure may result in increased left temporal theta and prenatal nicotine exposure may result in excessive beta. When reading a neonatal EEG, it is important to document current medications, but also to include medication/toxins that the child may still have in their system due to prenatal exposure.
Special thanks to Sophia French, MD. She earned a BS in biology at Denison University and an MD at the University of New Mexico School of Medicine. She recently completed her residency in child neurology at Oregon Health and Science University in Portland, Oregon, and has accepted a position as a general child neurologist at Golisano Children’s Hospital of Southwest Florida. Dr. French has a special interest in epilepsy and autoimmune disease.